Temperature controlled switch



R. c. WAPPNER 2,740,866

TEMPERATURE CONTROLLED SWITCH April 3, 1956 Filed Feb. 2'7, 1951 Bm mGHorneq United States Patent TEMPERATURE CONTROLLED SWITCH Ralph C.Wappn-er, Springfield, Ohio, assiguor to The Ohio Thermometer Company,Springfield, 01110, a corporation of Ohio Application February 27, 1951,Serial No. 213,007

11 Claims. (Cl. 200-142) This invention relates to temperaturecontrolled switch devices, particularly suitable for use in foodfreezing chests in conjunction with apparatus for signaling or otherwisegiving warning of temperature rise in the chest above a selectedcritical value.

It is of course the purpose of such apparatus to enable the householderor other user of the chest to remedy the ditficulty which resulted inthe rising temperature, before food spoilage occurs. A temperaturecontrolled or responsive switch for use in such apparatus should beconstructed for easy setting, be reliable and substantially foolproof inoperation, and be able to carry out its intended function unaffected byfrost formation and very low temperatures. It is thought that theinstant switch device achieves these ends in a better and more facilemanner than any similar device heretofore known.

The object of the invention is to simplify the construction as well asthe means and mode of operation of such switches, whereby they may notonly be economically manufactured, but will be more eflicient andreliable in use, adaptable to a wide range of applications, havingrelatively few parts and be unlikely to get out of repair.

A further object of the invention is to provide a switch of the typedescribed which is unaffected by formation of frost crystals.

A further object of the invention is to provide a switch which isaccurate in its response to change in temperature.

A further object of the invention is to provide in such a switch a meansfor insuring operation at a predetermined temperature whether thetemperature be increasing or decreasing.

A further object of the invention is to provide a switch which may beeasily set, and when set requires no further attention.

A further object of the invention is to provide a switch in which thereare substantially no moving mechanical parts. Y

A further object of the invention is to provide a switch possessing theadvantageous structural features, the inherent meritoriouscharacteristics and the mode of operation herein mentioned.

With the above primary and other incidental objects in view as will morefully appear in the specification, the invention intended to beprotected by Letters Patent consists of the features of construction,the parts and combinations thereof, and the mode of operation, ashereinafter described or illustrated in the accompanying drawings, ortheir equivalents.

In carrying out such objects there has been evolved a practicalembodiment of the invention wherein a signal switch for use in freezingchests includes a tube mounted for swinging motion to reversedpositions, flexible electrical leads introduced into the tube throughthe wall thereof and separated from one another, an electricallyconductive fluid material in the tube which flows from end to end of thetube in response to reversingthereof, such material bridging andinterconnecting the leads in one of the reversed positions of the tubeand flowing out w 2,740,866 Patented Apr. 3, 1956 of contact with theleads in the other position of the tube, and a congealable liquid in thetube flowable with the conductive material but relatively lighter thanthe conductive material so as to remain on the top thereof, thecongealable liquid solidifying at low temperatures to form a plug in thetube holding the conductive material in a selected end of the tubeirrespective of the position of the tube, the liquid decongealing atsome predetermined high temperature for escape of the blocked conductivematerial.

Referring to the drawing, wherein is found the preferred but obviouslynot necessarily the only form of embodiment of the invention,

Fig. 1 is a view in perspective of a temperature controlled switch inaccordance with the invention combined with mounting means forinstallation in a freezing chest or the like;

Fig. 2 is a view of the switch device in longitudinal section, showingit as positioned in the initial setting of the switch, conditioning itfor operation;

Fig. 3 is a view similar to Fig. 2 but showing the device turned degreesor reversed, being thus set to the position occupied in the operating orset position of the switch, and

Fig. 4 is a view similar to Fig. 3, showing the switch during thetemperature rise to and beyond the selected critical value.

Like parts are indicated by similar characters of reference throughoutthe several views.

In the illustrative embodiment shown in the drawing, the switchcomprises a tube 10 made of glass or a like non-conductor ofelectricity. The opposite ends of the tube are closed, one endpresenting a tapered or pointed formation and the other end being formedwith a relatively thick base portion 11. Intermediate its ends the tubeis pinched in to present a reduced diameter waist portion 12, suchportion defining in the tube What may be termed upper and lower wells 13and 14, the expressions upper and lower being in respect of the base 11.

Inside the tube 10 are first and second fiowable materials 15 and 16,which in their total volume approximately fill one of the wells 13 and14. The material 15 is an electrically conductive substance, for examplemercury. The material 16 is a congealable liquid, being composed ofWater and alcohol or commercial anti-freeze solution, combined inproportions designed to produce freezing and thawing of the liquidmaterial at a selected temperature. For a catalytic action to induceboth freezing and thawing more precisely at the selected temperature,the liquid material 16 carries in solution a number of small crystals 17which may, for example, be glass.

The tube 10 is interposed in an electrical signal circuit, and for thispurpose there is molded into the base 11 thereof two electricallyconductive prongs 18 and 19 which may be, as here shown, simply leadsfrom flexible electric Wires 21 and 22. The prongs or leads 18 and 19extend longitudinally through the base 11 and project in parallelseparated relation into the well 14. Being thus physically disconnected,there can be no flow of electrical current from one lead to the other inthe absence of a bridging or interconnecting medium. Such a bridgingmedium is supplied by the conductive material 15 which, when it collectsin the well 14, floods or encompasses both leads 13 and 19. Thus, theconductive material 15 represents a means whereby a circuit mayalternatively be closed and opened through the electric wires 21 and 22.It the tube 10 is held in the upright position of Fig. 4, the conductivematerial 15 collects in the bottom of well 14 and closes the circuitacross the contact points represented by the leads 18 and 19. By turningthe tube 180 degrees the reverse position of Fig. 2 is achieved and inthe course thereof the conductive material 15 will run out of the well14 and into the well 13, thus disconnecting leads 13 and 19 and openingthe circuit through wires 21 and 22 The liquid material it? ordinarilyflows with the conductive material 15 but does not mix therewith andbeing relatively lighter collects and remains on top thereof. Thefreezing or congealing of the liquid material 16 will result information of a plug adjacent the waist portion 12 of the tube preventingflow of the conductive material 15 from one well to the otherirrespective of the position of the tube.

In the use of the switch in a freezing chest or the like, the electricwires 21 and 22 are connected in a suitable signaling circuit and thetube ltl is mounted in the chest. in mounting the tube it is arrangedfor swinging motion, for example, as shown in Pig. 1 where the waistportion 12 receives a strap 23 from which projects a rod 24 rotatable ina mounting disc in setting the device for operation, the tube is firstadjusted to the position shown in Figs. 1 and 2 wherein the conductivematerial 15 and the liquid material to collect in the well l3 with. theliquid material supported on the conductive material in overlyingrelation thereto. The circuit through the leads 1% and 1% and the wires23 and 22; accordingly is at this time open. The tube is allowed toremain in this position until the low or lowering temperatures in thefreezing chest reduce the liquid material M to a congea ed mass. Thetube then may be swung to the position of Fig. 3 wherein the conductivematerial l tends to flow by gravity into the well 34 and close a circuitacross the leads l3 and 19, but is prevented from doing so by thematerial 145 which acts as a plug holding the conductive material in theupper well 13.

Now so long as the temperature in the freezing chest remains below thedegree selected as critical, the signaling circuit remains open, thecongealed plug of material 18 continuing to hold the material away fromleads 3.8 and 19. in the event, however, that the temperature in thefreezing chest rises to and exceeds the critical degree, the liquidmaterial l6 will begin to thaw and allow the conductive material 15 toescape downward into the well 14, as illustrated in Fig. 4. When asufficient quantity of the material 3.5 has collected in the bottom ofthe well 14 electrical connection is established between the leads itand closing a circuit there-across and through the wires 21 and 22 toenergize a signaling device.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated desirable, but which obviouslyis susceptible 0t modification in its form, proportions, detailconstruction and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprise but one of several. modes of putting the invention into effect.

laving thus described my invention, I claim:

1. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the wallthereof, a quantity of mercury or like solution in said tube which whenin said end of the tube encompasses said electrical leads andestablishes an electrical connection therebetween, and a quantity or" arelatively light congealable fluid in said tube normally flowable withsaid mercury like solution but maintaining its separate identity andoperative'as a plug in said tube when congealed to restrict the movementof said mercury or like solution.

2. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the wallthereof, an electrically conductive fluid material in said tubeeffective when collected in said one end of the tube to electricallyconnect said leads, the reversing of the position of said tube causingsaid material to how to and from said one end of the tube, and a secondfluid material relatively lighter than the first said fluid material andnormally flowable therewith but maintaining its separate identity, saidsecond fluid material being congealable in said tube at a predeterminedlow temperature to restrict the movement of said electrically conductivefluid material therein.

3. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the wallthereof, an electrically conductive fluid material in said tube flowablefrom end to end thereof in response to endwise reversing of the tube andeffective when collected in said one end of the tube to electricallyconnect said leads, and temperature responsive means normally flowablewith said iluid material but congealable as a separate entity in saidtube for controlling the movement of said fluid material.

t. A temperature controlled switch according to claim 3, characterizedin that said last named means is a liquid of diiierent specific gravitythan said fluid material and congealable at a predetermined lowtemperature to form a plug in said tube.

5. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the wallthereof, electrically conductive means movable in said tube from end toend thereof in response to endwise reversing of the tube and acting whenin said one end of the tube to bridge and interconnect said leads, and aliquid in said tube normally movable with said conductive means butmaintaining its separate identity and congealable at a predetermined lowtemperature to interpose a restriction to the movements of saidelectrically conductive means.

6. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the wallthereof. a quantity of electrically conductive fluid materials in saidtube fiowable from end to end thereof in response to endwise reversingof the tube and acting when in said one end of the tube to bridge andinterconnect said leads, and a quantity of a congealable liquid in saidtube of different specific gravity than said fluid material normallyilowable with said fluid material but maintaining its separate identityand said congealable liquid having a predetermined freeze and thawtemperature to thereby render the movements of said fluid materialsubject to temperature control.

7. A temperature controlled switch for repeated use in a food freezingchest or the like, including a closed tube of electricallynon-conductive material, said tube presenting a relatively heavy baseportion and a reduced diameter waist portion, said waist portion ineffect divid ing the interior of the tube into upper and lower wells,separated electrical leads extending through said base portion into saidlower well, a flowable electrically conductive material in said tube,which when in said lower well bridges and connects said leads, said tubebeing reversible in an endwise direction to cause said conductivematerial to run out of the lower Well and into the upper well and sodisconnect said leads, a relatively lighter liquid in said tubecongealable at a predetermined temperature to form a plug precludingmovement of said conductive material from one well to another, saidliquid decongealing atsaid predetermined temperature to permit flow ofthe conductive material.

8. A temperature controlled switch according to claim 7, characterizedby a catalyst in said congealable liquid in the form of glass crystals.

9. A signal switch or like device for use in freezing chests including atube mounted for endwise swinging motion to reversed positions, flexibleelectrical leads introduced into said tube through the wall thereof andseparated from one another, an electrically conductive fluid material insaid tube which flows from end to end of the tube in response toreversing thereof, said material bridging and interconnecting said leadsin one of said reversed positions of the tube and flowing out of contactwith said leads in the other position of the tube, and a congealableliquid in said tube fiowable with said conductive material butrelatively lighter than said conductive material so as to remain on thetop thereof, said congealable liquid solidifying at low temperatures toform a plug in said tube holding said conductive material in a selectedend of the tube irrespective of the position of the tube, said liquiddecongealing at a predetermined high temperature for escape of theblocked conductive material.

10. A temperature controlled switch for repeated use in a food freezingchest or the like, including a tube closed at its ends, separatedelectrical leads projecting into one end of said tube through the Wallthereof, an electrically conductive fluid material in said tubeeffective when collected in said one end of the tube to electricallyconnect said leads, the reversing of the position of said tube causingsaid material to flow to and from said one end of the tube, a secondfluid material in said tube normally flowable with the conductive fluidmaterial and congealable in said tube at a predetermined low temperatureto restrict the movement of said conductive fluid material therein, anda catalyst carried in said second fluid material to aid in precipitatingcongelation of said second fluid material at the selected lowtemperature.

11. A temperature controlled signal switch for repeated use in a foodfreezing chest or the like, including a tube closed at its ends andhaving a reduced diameter waist portion, a swivel mount for said tubeengaging the waist thereof and permitting said tube to be rotated aboutsaid mount to alternate inverted positions, said waist defining opposedwells in the ends of said tube, an electrically conductive fluidmaterial in said tube normally flowable with said conductive fluid andcongealable at a predetermined low temperature value to form a plugprecluding movement of said conductive material from one Well toanother, and flexible electrical leads attached to said tube andreceived in spaced relation in one well thereof to be bridged by saidconductive fluid when in said one well, said switch device beingadjusted to a first position in which lowering temperature values formsaid plug in overlying confining relation to said conductive materialand being then adjusted to an inverted position in which said plug holdssaid conductive material from flowing by gravity out of confinedposition, and said tube being readjustable back to said first positionfor a reforming of said plug after rising temperatures have reduced saidplug and permitted flow of conductive material thereby.

References Cited in the file of this patent UNITED STATES PATENTS922,883 Giese May 25, 1909 982,822 Hughes et al Jan. 31, 1911 1,645,201McBrien Oct. 11, 1927 2,315,425 Hill et al Mar. 30, 1943 2,453,177Abramson Nov. 9, 1948 OTHER REFERENCES Industrial and EngineeringChemistry, Analytical Edition, vol. 11, page 509 (1939).

